Probing the circumnuclear environment of NGC1275 with High-Resolution X-ray spectroscopy

Understand

NGC1275 is the Brightest Cluster Galaxy (BCG) in the Perseus cluster and hosts the active galactic nucleus (AGN) that is heating the central 100\,kpc of the intracluster medium (ICM) atmosphere via a regulated feedback loop.

• Here we use a deep 490ks Cycle-19 Chandra High-Energy Transmission Grating (HETG) observation of NGC1275 to study the anatomy of this AGN.
• The X-ray continuum is adequately described by an unabsorbed power-law with photon index $\Gamma\approx 1.9$, creating strong tension with the detected column of molecular gas seen via HCN and HCO$^+$ line absorption against the parsec-scale core/jet.
• This tension is resolved if we permit a composite X-ray source; allowing a column of $N_H\sim 8\times 10^{22}\,{\rm cm}^{-2}$ to cover $\sim 15$% of the X-ray emitter does produce a significant improvement in the statistical quality of the spectral fit.